For example, as a pipette used for dispensing liquid such as blood and liquid medicine, there has been known what is called a disposable pipette in which a pipette tip removably fitted thereto is disposed of after use in order to prevent cross contamination among liquids.
There has been a demand that quantitative operations using such a pipette at the time of suction and ejection of liquids be safely performed in order to prevent an inside of a cylinder from being contaminated by liquids, scattering of the liquids, and infection to pipette operators and contamination of inspection environments when, for example, the liquids are infectious samples. Further, it is desired that the pipette tip containing sucked liquid be disposed of by being separated from the pipette without being touched by hand after ejection of the liquid.
Conventionally, as a pipette of this type, there has been proposed a pipette including, as means for determining a suction/ejection amount of liquid based on an advancement/retreat amount of the piston and separating the pipette tip from the pipette so that the pipette tip is disposed of, a pipette tip separation mechanism including a sleeve movably fitted to an outer periphery of a cylinder, and an operating portion including an operation lever, an arm, gears, and a spring, in which the sleeve is pushed down by an operation of the operating portion so that the sleeve abuts against the pipette tip, thereby separating the pipette tip from a distal end of the cylinder (refer, for example, to Patent Literature 1).